Right rear light permanently on

Hello, at my Sportage 1.6 SL, the right (direction) rear light is constantly lit and no longer goes out. Position Light switch on automatic, turn signal on off. Fog light on 0. After closing the door and locking over FB, all the lights go out, except the right rear light. I already set the light on 0. I put the light on 1… then I closed the door, FB pressed 2x…everything out…except the right rear light. No matter which position I choose…if I then left with the FB Ele (2X press) it still remains. Maybe something quite banal and I don’t get on it? Would the rear light be removed tomorrow (2 screws) and let’s see if I see something visually. Maybe corrosion/crack currents? Are there circuit diagrams in the net? Or is this all about bus? Is maybe a electronics that I can sort of save? Would be grateful for tips.